August 28, 2011

Despite what your mother told you, fidgeting is a good thing

Most people would agree that "exercise" as part of healthy living means physical activity for the purpose of body conditioning-- jogging, pilates, lifting weights, and so forth. But physical activity for any purpose counts as exercise. Pacing while on the phone, doing your laundry or other chores, even nervously standing up and sitting down in a waiting room... it all counts, and it's all beneficial to your health.

Some even contend that these little daily activities are just as important as "regular exercise" for preventing chronic illness. As little as two weeks of inactivity has been found to cause adverse metabolic changes related to Type 2 diabetes in previously healthy individuals.

For similar reasons, increasing patient mobility is slowly becoming integrated into hospital care, especially for the critically ill in intensive care, who are more likely to be bedridden. A recent study found that patients who chose to walk around during a hospital stay, rather than sit still, were able to go home about a day-and-a-half sooner.

Despite what your mother told you, fidgeting (what physiologists call "spontaneous physical activity") is a good thing. It's been known for years that fidgeting can burn calories; a 1986 study looking at human metabolism found that fidgeting accounted for 100-800 kcal per day in their 177 subjects. However, not until recently have researchers understood how vital "spontaneous physical activity" could be to overall health. A 2008 review notes,
Spontaneous physical activity... can contribute significantly to interindividual differences in total daily energy expenditure. Cross-sectionally, spontaneous physical activity is inversely related to body weight; however, more importantly, spontaneous physical activity is inversely associated with weight gain in prospective studies.... Although spontaneous physical activity is a biologically driven behavior, interventions to increase nonexercise activity within the workplace and school hold promise in increasing daily energy expenditure for the average sedentary American.
Get up, move around!

August 8, 2011

Fish or fish oil for omega-3 goodness?

Yesterday I was asked to weigh in on a simple question that happens to have a complicated answer-- the best kind! The question: If you're trying to get the health benefits of increased dietary omega-3 fatty acids, is fish oil supplementation as good as eating oily fish?

Considering that several of the studies that support omega-3 benefits were done using fish oil supplementation, I suspect that the quick answer is "fish and fish oil are similar." At least as far as we can currently tell.

But the real answer depends on a number of things:

1. The ratio of omega-3 to other omega family fatty acids.

Because of the mechanism of fish's omega-3 benefits, it's necessary for omega-3 molecules to greatly outnumber competing omega molecules. (Omega-6 fatty acids are necessary, but are common in the Western diet.) Some supplements expressly include these competing fatty acids, which may decrease the potential for the omega-3 to do any good. Farmed fish may also be lower in omega-3 than their wild counterparts. (The overall ratio of omega-3 to other fats in your diet is also very important.)

2. Content of toxins such as heavy metals, PCBs, and other chemicals that may negate the long-term good stuff associated with omega-3.

Ocean waters contain some level of these contaminants, and so therefore do fish. The higher up the food chain the fish is and the older it is, the more they have tended to accumulate these toxins. For example, a tiny, short-lived, plankton-eating sardine will be safer to eat than a huge, long-lived, carnivorous tuna.

Supplement makers put their fish oils through a chemical purification process that reduces these contaminants, but they may also concentrate the fish oil, which would also concentrate any toxins present. An unconcentrated, well-purified supplement would probably have fewer toxins than carnivorous fish from the ocean.

3. What kind of processing the oil has undergone.

For fish, this is not of great concern except for cooking. Suffice it to say, deep frying your fish in peanut oil or being lavish with the butter may not produce the health benefits you want from fish. Eating raw fish would not alter the oil content, but comes with concerns of food-borne illness.

For supplements, processing is more industrial. Oil may be chemically cleaned, distilled, converted and re-converted. This processing should leave the oil safe to ingest and the omega-3 content intact, but only if done correctly. As fish oil gains in popularity as a supplement, some companies will no doubt be tempted to cut corners, to the detriment of consumers. Doing a little brand research may be helpful.

4. What else you are eating.

One of the benefits of reaching for whole foods rather than a supplement is that whole foods come with other nutrients. Fish is low in saturated fat and contains a large percentage of protein, which helps you feel satisfied after a meal. For example, 3 oz of cooked mackerel comes with 22 g of protein and nearly 2 g of minerals. Plus, if you are eating a piece of fish, you may be replacing something else on your menu that is not as nutritious.

July 17, 2011

Research findings: first impressions really do count the most

Informational messages are often a response to misinformation. A glaring example is the belief that HIV/AIDS is "only" a problem in the homosexual population, a pervasive belief that has exacerbated the spread of the virus in the heterosexual population for over 30 years. Such misinformation can continue to color judgment even after successful public education efforts, as shown in a recent study by Ullrich K. H. Ecker et al, of the University of Western Australia.

The research puts more evidence behind the adage that first impressions are the most lasting. Ecker conducted two experiments using a story about a warehouse fire, with "misinformation" being a statement that volatile chemicals were stored in the warehouse, and the "retraction" being a statement that the warehouse was empty.

The first experiment (n=161 undergraduate students) gauged the effect of varying the strength of the misinformation or the retraction by varying the repetitions (1, 3, or none) of each. Not surprisingly, there was a positive relationship between the number of repetitions and the answers on questionnaires about the warehouse fire story. But the experiment demonstrated that even when there was only 1 occurrence of misinformation, the 3 repetitions of the retraction did not reduce the influence of the misinformation back to zero.

In the second experiment (n=138 undergraduate students) Ecker et al simulated the effect of distractions on the continued influence of misinformation. "It is well established that cognitive load—- that is, the division of attention between two tasks—can have debilitating effects on memory retrieval," they write. "Cognitive load at misinformation encoding should therefore reduce the continued influence of misinformation." Indeed, the experimental results bear out this hypothesis, but again influence of the misinformation was never reduced to zero.

Ironically, a reference in the paper's introduction may have coded some "misinformation" about the authors' professional motives in my mind. They write,
To use a notorious real-world example, the Bush administration purportedly made 935 false statements about the security risk posed by Iraq in the 2 years following 9/11 (Lewis & Reading-Smith, 2008). It is possible that the reiteration of this misinformation (i.e., that Iraq possessed WMDs) led to particularly powerful continued influence (e.g., the widespread continued belief in the existence of WMDs in Iraq; Kull et al., 2003; Lewandowsky et al., 2005, 2009).
Although the paper does seem well-written and well-reported, that statement carried enough political-zealot baggage to make look more closely than usual for possible flaws in the rest of the paper. And, even though I am cognizant of that bias, there is no easy way to erase it from my mind.


Ecker, U. K. H., Lewandowsky, S., Swire, B., & Chang, D. 2011. Correcting false information in memory: Manipulating the strength of misinformation encoding and its retraction. Psychon Bull Rev. 18:570–578.

July 12, 2011

A Marylander cracks a lobster

Arthropods. They are a vital part of every ecosystem, and some are mesmerizingly beautiful to behold. But when arthropods interact with me, it's eat or be eaten!

Cracking and eating whole steamed blue crab has been an occasional** pleasure for me since childhood. Though some complain that "it's too much work," I find the challenge part of the fun, and I seem to have the knack. I have been called upon to demonstrate "crab picking" for many a newcomer to the crab-cracking table. Yet, despite being a veteran consumer of crustaceans, lobster has graced my plate only a handful of times, and a whole lobster never, until my recent trip to Maine. You see, I just didn't think I liked lobster.

And I was a cynic when people told me to reserve my judgment for those local New England crustaceans. I'll have to admit, I was wrong. Fresh from the sea, steamed and served with butter, the lobster was decadent and delicious.

For someone used to cracking crabs, the differing anatomy initially had me going slow. Can I eat this? Is that the same? I am still not sure whether I committed some kind of faux pas by getting "lump lobster meat" out of the body of the lobster. But I found many similarities, including the superior flavor (and inaccessibility) of the leg meat.

Lobster and crab are both relatively low-calorie proteins. But I found that lobster really needed butter to round out the flavor, which kind of kills any claim as a healthy food. In contrast, all crab needs is a little Old Bay!

** Whole local crabs are for special occasions. They are messy, time-consuming, and a bit pricey, but more importantly they are historically overfished. Harvesting of blue crabs, notably from the Chesapeake Bay, is managed and policed, but the population growth of crabs is limited by lack of dissolved oxygen, lack of submerged aquatic vegetation, and food web pressures. The American lobster is also a managed fishery species, and faces similar pressures.

July 7, 2011

There's a learning curve to online life

This is not my first blog or my first website. It is, however, my first blog and website directly associated to the same name on my driver's license.

Sometimes I look at the highly visible online lives of people only a few years younger than me, and thank my lucky stars that being born earlier denied me the opportunity to splay my life over the web before my adult judgment kicked in. However, the sheer volume of data flowing through our lives may provide a measure of cover. While there is a permanence to off-the cuff comments that previously did not exist, sites like Google seem to preferentially show data from sources that update frequently, which may act to bury old news out of sight of the casual browser.

Society will eventually adapt the new flow of personal information. People will become more savvy about their data stream. Perhaps throwaway comments, though recorded, will eventually be seen for what they are: junk. Maybe when we look at those embarrassing recorded moments, we'll more readily doubt their verisimilitude, and enjoy the quirks of humanity.

Meanwhile, there is little denying that the Internet will be a good thing for us, in the long run. The world seems to be slowly, but surely, coming together on its level ground, and that is why I'm here now.